Rolando Aquino

Peruvian Red Uakaris (Cacajao calvus ucayalii) Are Not Flooded-Forest Specialists

In the literature, particularly in primatological books, the Peruvian red uakari (Cacajao calvus ucayalii) is generally considered as a species that is specialized on living in flooded forest, despite existing evidence to the contrary. Here we review all available information on habitats where Cacajao calvus ucayalii have been observed. Most sightings are from terra firme, including palm swamps, or from mixed habitats, including terra firme and flooded forest. Therefore, we conclude that the species is not a flooded-forest specialist, but is flexible in its habitat requirements and generally uses terra firme forests or a mixture of habitats. Proper recognition of habitat requirements is important for understanding the ecoethological adaptations of a species and for appropriate conservation measures.

Sharing of sleeping sites betweenAotus vociferans with other mammals in the Peruvian Amazon

In studies performed during 1986, 1987, 1990, and 1991, in the seasonally flooded forest of the Napo and Nanay river basin, we recorded seven instances of cohabitation in night monkeys,Aotus vociferans. Cohabitation refers to the sharing of a sleeping site of one species of animal with other different species of animals (Aquino & Encarnacion, 1986). We also recorded two instances of cooccupation of night monkeys with other species of nocturnal mammals. Cooccupation refers to the independent use of different sleeping sites within the same tree by two or more species of animals. This study is the first report of cooccupation within the generaAotus. Forty-five sleeping trees with entrance holes were used by the night monkeys. In addition, one sleeping site was observed in a small concavity of the foliar sheath on aMauritia flexuosa palm.

Notes on the Natural History, Distribution and Conservation Status of the Andean Night Monkey, Aotus miconax Thomas, 1927

Abstract: The Andean night monkey Aotus miconax is found only in Perus northeastern cloud forests, and is one of the countrys three endemic primate species. Very little is known of this species; today largely limited to the records of Butchart et al. (1995) and a few museum specimens. Between 2005 and 2007, we observed A. miconax in various localities in the regions of Amazonas and San Martín, and recorded what we could of its natural history, distribution and conservation status. The Andean night monkey was observed to live in groups of two to four individuals, using sleeping sites at heights of 6 to 9 m. We have confirmed the presence of the species in 10 additional localities in Amazonas and San Martín, all between 900 and 2,788 m above sea level. It was recorded in various forests types, from primary to relict. Even though it is not hunted directly and can survive in disturbed habitats, the extremely high rate of deforestation in this area is threatening its long term survival. Research on the biology, natural history and ecological requirements of this species are much needed.

Geographic distribution and possible taxonomic distinction of Callicebus torquatus populations (Pitheciidae: Primates) in Peruvian Amazonia.

Population densities of yellow‐handed titi monkey (Callicebus torquatus) were estimated using transect census methods. Densities were 2.8 individuals/km2 in the upper Rio Itaya basin and 2.5 individuals/km2 in the lower Rio Algodón basin. Group size varied from two to five individuals, with an average of 2.9 individuals per group at the Rio Itaya. Groups were generally composed of two adults, probably the reproductive pair, with progeny from one to three previous birth seasons. Although the Rio Itaya population is phenotypically identical to populations from the rivers Nanay and Tigre, it differs from population on the rivers Napo and Putumayo. This suggests the existence of two disjunct populations of C. torquatus in Peruvian Amazonia whose taxonomic status warrants further examination. Am. J. Primatol. 70:1181–1186, 2008.

The range of the golden-mantle tamarin, Saguinus tripartitus (Milne Edwards, 1878): distributions and sympatry of four tamarin species in Colombia, Ecuador, and northern Peru

A detailed understanding of the range of the golden-mantle tamarin, Saguinus tripartitus (Milne Edwards, 1878), in Amazonian Peru and Ecuador is of particular relevance, not only because it is poorly known but also because it was on the basis of its supposed sympatry with the saddleback tamarin (S. fuscicollis lagonotus) that Thorington (Am J Primatol 15:367–371, 1988) argued that it is a distinct species rather than a saddleback tamarin subspecies, as was believed by Hershkovitz (Living new world monkeys, vol I. The University of Chicago Press, Chicago, 1977). A number of surveys have been carried out since 1988 in the supposed range of S. tripartitus, in both Ecuador and Peru. Here we summarize and discuss these issues and provide a new suggestion for the geographic range of this species; that is, between the ríos Napo and Curaray in Peru and extending east into Ecuador. We also review current evidence for the distributions of Spix’s black-mantle tamarin (S. nigricollis nigricollis), Graells’ black-mantle tamarin (S. n. graellsi), and the saddleback tamarin (S. fuscicollis lagonotus), which are also poorly known, and examine the evidence regarding sympatry between them. We conclude that despite the existence of a number of specimens with collecting localities that indicate overlap in their geographic ranges, the fact that the four tamarin species are of similar size and undoubtedly very similar in their feeding habits militates strongly against the occurrence of sympatry among them.

Distribution and Abundance of White-Fronted Spider Monkeys, Ateles belzebuth (Atelidae), and Threats to Their Survival in Peruvian Amazonia

The white-fronted spider monkey, Ateles belzebuth, is listed as ‘Endangered’ according to the IUCN classification. In Peru it is found in the departments of Loreto, San Martín, Amazonas and Cajamarca, but detailed data on its geographic distribution, population densities and conservation status are scarce. In order to obtain such information, we conducted transect censuses on the Río Aushiri and Río San Antonio (right bank of Río Napo), and between the Río Curaray and the Río Arabela and Río Nashiño, respectively, and made additional explorations on the northern and southern banks of the Río Marañón. We obtained 48 sightings along 761 km of census transect. Group size and population densities were lower in an area with high hunting pressure compared to areas with medium or low hunting pressure. Besides hunting, increasing deforestation is a major threat to the survival of A. belzebuth in Peruvian Amazonia.

Geographic distribution and demography of Pithecia aequatorialis (pitheciidae) in Peruvian Amazonia

To study the geographic distribution and demographic characteristics of Pithecia aequatorialis in Peruvian Amazonia, we undertook surveys and transect census in three river basins (Río Itaya, Río Tigre and Río Curaray) between 2004 and 2008. A total of 123 groups of P. aequatorialis was encountered during 1623 km of transect walks. Group size was uniform among the three areas (3.4–3.6 individuals), but surprisingly, population densities were higher in the area with strong hunting pressure (Río Itaya: 7.8 ind./km2, vs. 5.6 and 5.9 km2 in the Río Tigre and Río Curaray basins, respectively). The most common group composition included an adult pair with one offspring. Groups with more than one adult male and/or female accounted for 35% of sightings. Our observations extend P. aequatorialis range in Peru further south to the area between the Río Tigre and Río Corrientes, but exclude the area to the north between the Río Curaray and Río Napo. These findings are in contrast to previous distribution maps. P. aequatorialis was rarely seen in interspecific association during our censuses. Am. J. Primatol. 71:964–968, 2009.

Geographic comparison of plant genera used in frugivory among the pitheciids Cacajao, Callicebus, Chiropotes, and Pithecia.

Pitheciids are known for their frugivorous diets, but there has been no broad‐scale comparison of fruit genera used by these primates that range across five geographic regions in South America. We compiled 31 fruit lists from data collected from 18 species (three Cacajao, six Callicebus, five Chiropotes, and four Pithecia) at 26 study sites in six countries. Together, these lists contained 455 plant genera from 96 families. We predicted that 1) closely related Chiropotes and Cacajao would demonstrate the greatest similarity in fruit lists; 2) pitheciids living in closer geographic proximity would have greater similarities in fruit lists; and 3) fruit genus richness would be lower in lists from forest fragments than continuous forests. Fruit genus richness was greatest for the composite Chiropotes list, even though Pithecia had the greatest overall sampling effort. We also found that the Callicebus composite fruit list had lower similarity scores in comparison with the composite food lists of the other three genera (both within and between geographic areas). Chiropotes and Pithecia showed strongest similarities in fruit lists, followed by sister taxa Chiropotes and Cacajao. Overall, pitheciids in closer proximity had more similarities in their fruit list, and this pattern was evident in the fruit lists for both Callicebus and Chiropotes. There was no difference in the number of fruit genera used by pitheciids in habitat fragments and continuous forest. Our findings demonstrate that pitheciids use a variety of fruit genera, but phylogenetic and geographic patterns in fruit use are not consistent across all pitheciid genera. This study represents the most extensive examination of pitheciid fruit consumption to date, but future research is needed to investigate the extent to which the trends in fruit genus richness noted here are attributable to habitat differences among study sites, differences in feeding ecology, or a combination of both. Am. J. Primatol. 78:493–506, 2016.

Diversity, Abundance and Habitats of the Primates in the Río Curaray Basin, Peruvian Amazonia

Abstract: Western Amazonia is one of the regions of the world with the highest terrestrial biodiversity. We conducted transect censuses between November and December 2012 in order to determine the diversity and the densities of primate populations, and their group sizes and habitat use in the Río Curaray region. During 610 km of transect surveys, we encountered 304 groups of 13 primate species. Woolly monkeys, Lagothrix poeppigii, were the most frequently observed (n = 49 sightings) and pygmy marmosets, Cebuella pygmaea, the least (n = 8). Population density was lowest for howler monkeys, Alouatta seniculus (9.8 individuals km-2) and saki monkeys, Pithecia aequatorialis (11.8 individuals km-2) and highest for squirrel monkeys, Saimiri macrodon (65.0 individuals km-2) and woolly monkeys (65.3 individuals km-2). Primate groups were most frequently encountered in “palmales de altura” (97 encounters of 12 species). In conclusion, the Río Curaray region harbors a very high diversity of primates, matching other sites in Amazonia and worldwide, and populations there are evidently healthy and well conserved. We recommend the creation of a protected area contiguous with the Yasuní National Park in Ecuador.

Current Status and Threats to Lagothrix flavicauda and Other Primates in Montane Forest of the Región Huánuco

Abstract: We report on the current status and threats to Lagothrix flavicauda and other primates that inhabit montane forest of the Región Huánuco; an area that has been little explored with regard to its primate fauna and other mammals. During 618 km of transect walks in June–July 2014 and September–October 2014, we encountered 47 groups of five primate species, the most common being Alouatta seniculus (15 groups) and Lagothrix flavicauda (13 groups). We also observed four groups of Aotus sp. in the Miraflores census site. Lagothrix flavicauda was seen only in the microbasin of the Río Chontayacu, and Ateles chamek in the upper Río Huallaga. The primates were living in patches of primary and remnant forest surrounded by farmland and pasture except in Chontayacu, where the forest is still dense and extensive. Of the three species with complete counts, group sizes were largest for L. flavicauda (mean 13.6 ±7.8, n = 5) and smallest for A. seniculus (mean 5 ±3.5, n = 11). Population densities were highest for L. flavicauda (20.8 ind./km2) and lowest for Sapajus macrocephalus (2.7 ind./km2). Deforestation for agriculture and cattle ranching and hunting are the major threats to the survival of these primates. Sapajus macrocephalus and Cebus yuracus were the most affected by these threats, particularly in the Río Chinchao microbasin,